(1) Field of the Invention
The present invention relates to novel antitumor anthracyclinone glycosides and their preparation method.
(2) Description of the Prior Art
Various types of anthracyclinone glycosides have been provided by fermentative, semi-synthetic and fully synthetic processes. For example, adriamycin (U.S. Pat. No. 3,803,124), carminomycin (J. Antibiotics 27, 254 (1974)), dihydrocarminomycin (Antibiotiki 21, 1008 (1976)) and rhodomycin analogs (Japan Kokai No. 56-15299 (1981)) have been reported (a review article is found in the Japanese Journal of Antibiotics 30, S-70.about.S-84 (1977). Among this family of antibiotics, adriamycin and daunomycin (U.S. Pat. No. 3,616,242) which have widely been used clinically as antitumor chemotherapeutics are known to often cause undesirable side effects.